The present inventors have earlier developed an apparatus for separating highly concentrated alcohol from alcohol (See Patent Document 1).                Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-314724        
In this particular separating apparatus, an alcohol solution is filled in an ultrasonic atomization chamber of a closed structure, the alcohol solution in the ultrasonic atomization chamber is ultrasonically vibrated by an ultrasonic vibrator to be atomized into mists, and the atomized mists are condensed and collected to separate a highly concentrated alcohol solution. This separating apparatus is able to separate highly concentrated alcohol in the following mechanism.
When compared with water, alcohol is easier to migrate to the surface portion of a solution, and the solution has a higher concentration of alcohol at the surface portion. In such a state, when the solution is ultrasonically vibrated, the highly concentrated alcohol turns into mists of fine particles and is released into the air under the effect of energy generated by the ultrasonic vibration. The mists released into the air have a high concentration of alcohol. This is because the solution at the surface, where the alcohol concentration is high, is easier to turn into mists. Consequently, when the mists are condensed and collected, a highly concentrated alcohol solution is obtained. This method enables a highly concentrated alcohol solution to be separated without heating the solution. Thus, it becomes possible to separate a target substance for a higher concentration with lower energy consumption. And, in absence of exposure to heat, this method carries the advantage that a target substance can be separated without being deteriorated.